Interference of Advanced Glycation End-products signaling with collagen cross-linking in human endothelium

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: MON 758-775-Beta Cells, Glucose Control & Complications
Basic/Translational
Monday, June 17, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board MON-767
Christos Adamopoulos*1, Christina Piperi1, Penelope Korkolopoulou2, Georgia Dalagiorgou1, Anastasia Spyropoulou1, Antonios N Gargalionis1, Eleni A Kandaraki1 and Athanasios G Papavassiliou1
1University of Athens Medical School, Athens, Greece, 2University of Athens Medical School
Introduction: Maintenance of extracellular matrix (ECM) stability is critical for vascular remodeling associated with cardiovascular diseases. Covalent cross-linking of collagen and elastin initiated by the copper-dependent lysyl oxidase (LOX) is a central event assuring ECM stability and vascular homeostasis. LOX downregulation leads to endothelial dysfunction characteristic of early atherosclerotic stages, whereas its upregulation in vascular cells can induce neointimal thickening in atherosclerosis and restenosis.

Advanced Glycation End-products (AGEs), the highly reactive products of non-enzymatic glycation of proteins, lipids and nucleic acids, contribute to endothelial dysfunction, atherosclerosis and vascular injury under both normal and diabetic conditions.

The aim of the present study was to investigate the effect of AGEs in regulation of LOX gene/protein expression in human endothelial cells and to explore the potential functional impact of this interaction in an animal model.

Methods: Human aortic endothelial cells (HAECs) were treated with increasing concentrations (100, 200 μg/ml) of unmodified or glycated-bovine serum albumin (AGE-BSA) for different periods of time (24, 48, 72 h). LOX and receptor for AGE (RAGE) expression in HAECS was assessed by quantitative real-time polymerase chain reaction (real-time PCR) and flow cytometry. The binding capacity of AGE-induced transcription factors Nuclear Factor-κΒ (NF-κΒ) and Activator Protein-1 (AP-1) was monitored by electrophoretic mobility-shift assay (EMSA).

Aortic endothelium of normal rats fed with low- or high-AGE content diet for three months was further investigated for AGE, RAGE and LOX expression as well as further morphological alterations.

Main results: Treatment of HAECs with AGE-BSA triggered LOX transcription and protein expression in a time- and dose-dependent manner. This induction was mediated by activation and binding of NF-κΒ and AP-1 transcription factors to LOX gene promoter. Significantly increased expression of ΑGEs, RAGE and LOX was observed in the aortic endothelium of normal rats fed with high-AGE diet compared to controls.

Conclusions: Our data support the regulation of LOX gene by the AGE-induced transcription factors NF-κΒ and AP-1 in endothelial cells. Upregulation of LOX expression in endothelium constitutes a potential mechanism for compromised ECM integrity and function that characterizes microvascular complications associated with metabolic diseases and aging.

Nothing to Disclose: CA, CP, PK, GD, AS, ANG, EAK, AGP

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: This research has been co-financed by the European Union (European Social Fund – ESF) and Greek national funds through the Operational Program "Education and Lifelong Learning" of the National Strategic Reference Framework (NSRF) - Research Funding Program: Heracleitus II. Investing in knowledge society through the European Social Fund.